Mobile communication devices are in widespread use throughout the world, and in particular in metropolitan regions of the world. These devices are typically powered by a rechargeable battery to avoid the expense of frequently replacing battery cells. The rechargeable battery is typically disposed in a battery compartment of the mobile communication device, and covered by section of the housing referred to as a battery cover. To recharge the battery, the mobile communication device is connected to an external power supply and charging circuitry inside the mobile communication device controls charging of the battery. There are two different charger arrangements, commonly referred to as single and dual path charging.
A single path charging arrangement powers the mobile communication device from the battery voltage during charging, while the dual path charging arrangement powers the mobile communication device from the external power source at least initially, until the battery voltage rises sufficiently to power the mobile communication device. In some dual path charging arrangements the mobile communication device may always be powered by the external power source while the mobile communication device is connected to the external power source. At the same time, the battery is charged via a second path. The advantage of dual path charging is that immediately upon connecting the mobile communication device to the external power supply the user may use the mobile communication device, regardless of the battery state of charge. This has not been possible in a single path charging arrangement when the battery is substantially discharged because the battery voltage must first rise to a level capable of powering all systems of the mobile communication device. This causes an annoying delay for the user, and also limited user feedback as the communication device cannot power up and give a display message showing charging status or other information. The single path scheme uses fewer components, and is less expensive to implement. It also avoids the complexities of precise supply switching required in dual path when the external power supply is attached or removed. Therefore there is a need a charging circuit scheme that allows operation of the mobile communication device while the battery voltage is low, but without the expense of a dual path scheme.